The scope and connection of Leviticus with Numbers

The Book of Leviticus contains the revelation of God sitting upon
the throne, where He places Himself that He may be approached by the
people, as far as they could come; that of the priesthood brought into
proximity to the throne, as far as men could have access to it; and
then the promulgation of the commandments relative to these two great
facts, in that which concerned the generality of the people.

In Numbers we have the service and walk of the people, figuratively
of the saints through this world: and, consequently, that which
relates to the Levites, and the journey through the wilderness. Now,
as Leviticus ended with regulations and warnings respecting the
possession of the land, and that with regard to the rights of God, and
consequently to the rights of His people, the Book of Numbers brings
us through the wilderness to the moment before the entrance of the
people into the land at the end of the wilderness journey, and speaks
of that grace which justifies the people at the close, notwithstanding
all their unfaithfulness.

The wilderness journey

It is important to keep in mind that as to the efficacy of
redemption the people were brought to God at Sinai (Ex. 15: 13 and 19:
4). All in this respect was complete (compare the thief on the cross
and Col. 1: 12). The wilderness journey is a distinct thing; no part
of the purpose of God, but of His ways with us. Hence it is here
"if" comes in and the time of testing. Jordan coalescing
with the Red Sea, coming out and going in (only the ark was in
Jordan), there was no question of judgment or enemies. It is the
experimental realisation of our death and resurrection with
Christ. But as to the journey we must reach the goal to get in.